This is DEVO10 directions. I'm not positive about all others. Once you've upgraded your TX it will be a USB drive. On the USB drive there will be a "Models" folder. See attachment. You copy and paste the Model#.ini (Model##.ini if it's 10 and over) into that folder. Name it with a number that is open. So if model5.ini is not being used rename the file you want to use to model5.ini and paste over the old file.
Have fun! I do.
-Jasen